Polymerization Of Thiophene Monomers Research Articles

AmPhos Pd-Catalyzed Suzuki–Miyaura Catalyst-Transfer Condensation Polymerization: Narrower Dispersity by Mixing the Catalyst and Base Prior to Polymerization

Several palladium catalysts with bulky phosphine ligands other than t-Bu3P were investigated for Suzuki–Miyaura catalyst-transfer condensation polymerization (CTCP). When the model reaction of 2,5-dibromothiophene with phenylboronic acid ester was carried out with a variety of Pd precatalysts in the presence of K3PO4 as a base, we found that the use of di-tert-butyl(4-dimethylaminophenyl)phosphine (AmPhos) Pd as a precatalyst resulted in exclusive formation of diphenyl-substituted thiophene. Polymerization of thiophene monomer and fluorene monomer with an initiator generated in situ from AmPhos Pd precatalyst and 4-iodobenzonitrile proceeded via the CTCP mechanism, affording polythiophene (P3HT) and polyfluorene with low dispersity and controlled polymer ends. Furthermore, (tolyl)PdAmPhos(Br) (7) was synthesized, and its polymerization properties were investigated. We found that polymerization of thiophene monomer with a mixture of 7 and CsF that had been stirred for 1 h prior to polymerization afforded P...

Improvement of the Cycle Performance of LiNi<sub>0.5</sub>Mn<sub>1.5</sub>O<sub>4 </sub> Cathode Active Materials by In-Situ Coating with Poly(3,4-Ethylenedioxythiophene)

LiNi0.5Mn1.5O4 (LNMO)/poly(3,4-ethylenedioxythiophene) (PEDOT) composite cathode materials were prepared through in-situ polymerization of thiophene monomer (EDOT), with ammonium persulphate (APS) as oxidizing agent, p-toluenesulfonic acid (PTSA) as dopant. The morphology, amount of PEDOT coating, electrochemical properties of LNMO/PEDOT were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and galvanostatic charge and discharge tests. The results show that the composite materials show better cycle performance than bare LNMO.

Synthesis, Characterization and Electrical Conductivity of Zinc Oxide Nanoparticles Embedded in Polythiophene Nanocomposites

Polythiophene/ZnO (PTh/ZnO) nanocomposites composed of conducting polymer PTh were prepared by chemical polymerization of thiophene monomer using FeCl3 as an oxidant and ZnO nanoparticles by reverse micellar method. The nanocomposites were also characterized using FTIR, SEM, TEM, and XRD. It was found that the electrical conductivity of the nanocomposites first increased conductivity of the nanocomposite first increased but later on decreased as the temperature increased. Electrical conductivity of nanocomposite containing polymer matrices and zinc oxide nanoparticles showed good stability in terms of electrical conductivity retention up to 110 � C. Scanning electron micrographs showed globular particles and the presence of clusters of composite particles. Transmission electron micrographic (TEM) analyses revealed the particle size of the composite to be in the range 22–17 nm. Thermal analyses (TG/DTA) revealed the outstanding stability of PTP–ZnO composites compared to PTP. The conductivity of PTP and of PTP–ZnO composite was of the order of 10 −4 –10 −2 Sc m −1 .

A direct route to polythiophenes displaying lateral substituents: Easy one-step synthesis and polymerization of thiophene monomers substituted by a dimethylenecarboxylate (CH2CH2COOR) appendage on the 3-position

Thiophene monomers displaying a dimethylenecar- boxylate (CH2CH2COOR) substituent on the 3-position of the aromatic ring can be easily obtained and in one step from the electrochemically induced reaction of 3-bromothiophene with the corresponding acrylate (CH2=CHCOOR). The synthesis of the ethyl ester monomer, of related 2,5-dihalogenothiophenes, and their polymerization are reported. Despite the surprisingly low solubilities displayed by the polymers, a full spectroscopic characterization could be performed and the data fully analyzed. Oxidative polymerizations (FeCl3 or electropolymerization) yield a regioirregular polythiophene, with 60–70% of head-to-tail diads. Both experimental and theoretical results suggest that the nonconjugated ester plays a very minor role - if any - in the polymerizations under oxidative conditions, but has a significant influence on the polymer properties. Preliminary attempts to polymerize the dihalogenothiophenes under reductive conditions were hampered by the even lower solubilities exhibited by the regioregular oligomers.

Highly Ordered Poly(thiophene)s Prepared in Mesoporous Silica Nanoparticles

Nanostructured PEDOT was synthesized using mesoporous silica as a nano-template. The polymerization of thiophene monomers was performed with an oxidant and mesoporous silica nanoparticles. The silica particles took essential role in absorbing monomers and oxidant molecules, and growth of polymers inside their pores. As prepared polymer/silica composite was treated with HF solution to remove silica template to result in 1D wire structure and mesh type porous 3D structures from SBA-15 and KIT-6 template, respectively. The average size of the poly(thiophene) wires was 10 15 nm, which was matched well to the pores size of the silica templates, as determined from an electron microscopy. At optimized condition, the room temperature electrical conductivities of the PEDOT grown from SBA-15 and KIT-6 template were similar as 1.1 and 1.0 S/cm, respectively. However, the evolution of the PEDOT conductivity versus temperature was different depending on the templates. These results gave a unique chance to tailor made 3 dimensional structure as well as properties of conductive polymer.

The Characterization and Gas Sensing Properties of Polythiophene Coated V<sub>2</sub>O<sub>5</sub> Nanotubes

Polythiophene (PTP) coated V2O5 nanotubes were prepared by an in-situ polymerization of thiophene monomers in the presence of prepared V2O5 nanotubes. The nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which proved the polymerization of thiophene monomer and the strong interaction between polythiophene and V2O5 nanotubes (VONTs). The gas sensing properties of PTP coated V2O5 nanotubes were studied at room temperature, which was found that PTP coated V2O5 nanotubes could detect ethanol with much higher sensitivity than pure VONTs. The sensing mechanism of PTP coated V2O5 nanotubes to ethanol is presumed to be the synergetic interaction between polythiophene (PTP) and V2O5 nanotubes.